Abstract [en]

Diabetic foot complications impose a major economic burden to society and lead to decreased quality of life for the patients. Preventive measures and effective diagnostic methods are necessary to limit the incidence of foot ulcers and lower limb amputations. This report covers a systematic review of the scientific literature on temperature measurements for prevention of diabetic foot disorders and a feasibility study of a new LCT-technology that shows the warmth distribution of the feet. The target readers for the report are decision makers, medical professionals and patients.

The epidemiology of the diabetic foot is explored as well as guidelines and current practices for prevention and treatment. Further are the costs of diabetic foot ulcers estimated, based on the literature, and the value of early diagnosis is discussed. There is, however, a large variation in the basic data, depending on variations in study populations and country of origin in the included literature, which has lead to fairly indefinite estimates. Foot ulcer costs in Sweden are estimated to 851 - 1625 million SEK each year. The average cost for a case of foot ulcer, from diagnosis to healing, is 99 000 - 189 000 SEK. The highest costs are for hospitalisation, while prevention and diagnostic measures incur relatively small expenses. This means that reduction of hospital admissions through preventive care has a potential to be cost effective. Implementation of multi-disciplinary foot-care teams during the past years has led to dramatic reductions in the frequency of lower limb amputations, but there is still a lot to be gained by early diagnosis and prevention. The estimated number of foot ulcers in Sweden today is 8600. With an amputation incidence of 15 % this indicates that 1300 ulcers each year will result in an amputation, incurring costs estimated to be 324 - 601 million SEK.

Studies show that increased temperature can be used as a predictive sign of future ulceration of the diabetic foot. The patient seldom feels pain because of peripheral neuropathy, and thus, temperature can be an important indicator of foot disorders that otherwise would have passed undetected. Recommendations about temperature evaluation are given in consensus statements and guidelines, in Sweden and elsewhere, but instrumental measurements are seldom performed. Scanning with an IR-thermometer is one available, but time consuming, method and today's practice is palpation of the foot temperature.

Studies of daily home monitoring of foot temperature points at a more than 60 % decreased incidence of ulcers. There is, however, nothing in the studied literature to indicate that the method has been adopted for standard use anywhere. There are mainly two technologies for temperature measurement that have had an experimental clinical application. They are scanning with IR-thermometer and liquid crystal thermography (LCT). Both technologies have low costs and are easy to use.

Results that have not been published previously are reported from the feasibility study of the new LCT foot indicator SpectraSole Pro 1000. The patients initially had their foot status determined in a standard examination, according to current practice, and were thereafter examined with the LCT instrument. Findings from the examinations with SpectraSole Pro 1000 were then analysed and compared to the preceding ordinary examinations. 69 examinations were performed in 65 patients. An examination with SpectraSole Pro 1000 was considered easy and quick to perform and the instrument clearly visualised problem areas of the foot, which might motivate patients to a higher compliance and contribute to a better foot-related behaviour.

SpectraSole Pro 1000 detected 75 % of the foot problems among the patients in the three groups with the worst foot status. Among all patients the instrument detected six cases that had been missed in the ordinary examination. This leads to the conclusion that the foot indicator gives additional information, but cannot replace the standard inspection of the foot. To be able to assess how the incidence of ulcers and amputations is influenced, a larger trial must be performed in the primary care setting, preferably with a long term follow up to assess the outcome of prevented foot complications.

Based on the studied literature, the conclusion can be drawn that regular temperature monitoring of diabetic feet probably is of value. However, temperature monitoring can only be a complement to the current practice for foot examination. If temperature monitoring was to be included in a regular practice, costs for determination of foot status and primary foot care would increase, while potential savings would be on specialist care and hospitalisation. A rapid diagnosis and early intervention is crucial for the healing of lesions of the diabetic foot and a redistribution of resources to early interventions might be necessary.